Internal mold release agents for polyurethane materials

Abstract

An internal mold release agent (IMRA) which effectively releases a cured polyurethane (PU) material from a metal, in particular steel, mold. The IMRA is a surface active agent containing phosphorus or a combination (blend or reaction product) of the agent with other chemicals. In one embodiment the agent is a phosphate ester. In one embodiment the agent is polyoxyethylene alkyl phosphate ester. A polyurethane formulation comprising the IMRA has high formulation stability, clean release, low release strength, and high product transparency.

What is claimed: 
     
         1 . An internal mold release agent for a polyurethane molding resin comprising a polyoxyethylene alkyl phosphate ester, a blend or a reaction product of a polyoxyethylene alkyl phosphate ester. 
     
     
         2 . The internal mold release agent of  claim 1  wherein the polyoxyethylene alkyl phosphate ester comprises the structure: 
       
         
           
           
               
               
           
         
         wherein
 R can be hydrogen, hydrocarbyl, or substituted hydrocarbyl; 
 Y can be hydrogen, hydrocarbyl, or substituted hydrocarbyl; and 
 n is an integer from 1 to 3. 
 
       
     
     
         3 . The internal mold release agent of  claim 1  wherein the polyoxyethylene alkyl phosphate ester comprises the structure: 
       
         
           
           
               
               
           
         
         wherein R is hydrogen; Y is alkyl; and n is an integer from 1 to 3. 
       
     
     
         4 . A polyurethane molding composition comprising an effective amount of the internal mold release agent of  claim 1 . 
     
     
         5 . The polyurethane molding composition of  claim 4  wherein the polyoxyethylene alkyl phosphate ester comprises the structure: 
       
         
           
           
               
               
           
         
         wherein
 R can be hydrogen, hydrocarbyl, or substituted hydrocarbyl; 
 Y can be hydrogen, hydrocarbyl, or substituted hydrocarbyl; and 
 n is an integer from 1 to 3. 
 
       
     
     
         6 . The polyurethane molding composition of  claim 4  wherein the polyurethane molding composition comprises a polyol composition and a separate polyisocyanate composition; and at least one of the polyol composition or polyisocyanate composition includes an effective amount of the internal mold release agent. 
     
     
         7 . The polyurethane molding composition of  claim 4  wherein the polyurethane molding composition comprises a polyisocyanate composition; and a separate polyol composition including the effective amount of the internal mold release agent. 
     
     
         8 . The polyurethane molding composition of  claim 4  wherein the polyurethane molding composition comprises a polyisocyanate composition; and a separate polyether polyol composition including the effective amount of the internal mold release agent. 
     
     
         9 . A method of reducing adhesion of cured reaction products of a polyurethane composition to a metal mold comprising adding an effective amount of the internal mold release agent of  claim 1  to the polyurethane composition before curing the polyurethane composition to form the cured reaction products. 
     
     
         10 . A process for production of a molded polyurethane article, comprising:
 providing a mold defining a mold cavity;   providing a polyurethane composition comprising an effective amount of the internal mold release agent of  claim 1 ;   disposing the polyurethane composition in the mold cavity; and   curing the polyurethane composition to form cured reaction products in the mold cavity; wherein the cured reaction products have a lessened adhesion to the mold as compared to cured reaction products formed from a polyurethane composition without the effective amount of the internal mold release agent.   
     
     
         11 . The process of  claim 10  wherein the polyurethane composition comprises a polyol composition and a separate polyisocyanate composition, wherein at least one of the polyol composition or the polyisocyanate composition includes the effective amount of an internal mold release agent. 
     
     
         12 . The process of  claim 10  wherein the polyurethane composition comprises a polyol composition and a separate polyisocyanate composition, wherein the effective amount of an internal mold release agent is added to the polyurethane composition after mixing of the polyol composition and the polyisocyanate composition.